Applications increasingly demand DC-DC converters with high gains of 10× or higher in addition to high efficiency, high power, and wide regulation capability. The traditional boost has found its application when the voltage gain is moderate. However, as the voltage gain increases to greater than four, the duty cycle of the boost converter will approach one, leading to the freewheel diode operating in a high current and narrow pulse condition. Thus, the recovery loss and conduction loss will both increase dramatically, while the regulation margin will be limited.